Rock fracture mechanism of air-deck charge blasting considering the action effect of blasting gas

Abstract

This paper primarily focuses on examining the impact of blasting gas, studying the rock fracture mechanism of air-deck charge blasting, and analyzing the evolutionary characteristics of blasting stress, the law of damage distribution, and the fracture characteristics in rock specimens. Firstly, indoor blasting model experiments are conducted and analyzed by combining the computed tomography (CT) scanning method, three-dimensional (3D) reconstruction technology, and fractal damage theory. The experimental results indicate that the distribution characteristics of rock damage in air-deck charge blasting are mainly determined by factors such as charge segment position, air-deck length, and position. Next, a numerical simulation method based on the coupling analysis of Lagrangian finite element and Euler finite volume is proposed to enable the numerical simulation of rock blasting fracture while considering the action effect of blasting gas. The analysis of the numerical simulation results reveals that the rock failure near the blasthole, under the influence of blasting gas, is primarily due to tensile failure, whereas the rock failure in the distant area is predominantly caused by shear failure. Furthermore, during the process of rock fragmentation by blasting gas, the initial interaction between the blasting gas and rock is the main controlling factor for rock damage and failure, whereas the subsequent reflection and transmission of blasting gas have a relatively minor impact on rock damage and failure.